The wide usage of fabricated roof trusses in recent times and the ever-increasing size of these trusses has led to the need for on-the-job-site apparatuses for fabricating the trusses so that they do not have to be transported over roadways. To satisfy this need, certain fixed and portable wooden truss fabricating plants have been proposed in the prior art. To comply with the duty to disclose known prior art under 37 C.F.R. 1.56, the below-listed prior United States patents are made of record herein: U.S. Pat. Nos. 3,068,483; 3,379,354; 3,693,542; 3,752,467; 3,933,348; 4,071,061.
Generally speaking, the prior art proposals pertaining to apparatuses for fabricating wooden trusses on the job site have not proven entirely practical because of undue complication and cost of the mechanisms. Additionally, where the customary hydraulically operated C-clamp for applying nailing clips to truss joints is tethered on the apparatus as in U.S. Pat. No. 3,379,354, there is insufficient freedom of movement of the clamp relative to the work, in some cases requiring shifting of the truss lumber on the support bed of the apparatus in the course of the fabricating process.
To overcome these and other difficulties of the prior art, the present invention is embodied in a more simplified and much more versatile portable truss fabricating apparatus which basically comprises a transport trailer having a bed for the support of truss lumber in a convenient and secure manner on the job site. The trailer bed has longitudinal and transverse truss lumber supporting members, some of which are readily extendable on the job site so that the complete truss framework can be supported. The extendable support members of the trailer bed can be retracted or removed during transport of the apparatus behind a towing vehicle. Adjustable outrigger jacks are provided on the trailer bed to level and stabilize the bed during usage.
A dominant feature of the invention resides in the provision at one side of the trailer bed of an upright support for a double articulated boom arrangement which supports the hydraulically operated C-clamp in suspended relationship to an auxiliary counterweighted boom which in turn is suspended for universal movement from the main boom swiveled to the top of the side upright support. The operator of the clamp for placing the nailing clips at the truss joints is freed from the task of carrying the heavy clamp and the operator has almost complete freedom of movement over the entire truss area so that all joints can be secured with the clamp without the necessity for shifting the lumber. This is the main improvement feature of the invention which distinguishes it from the prior art.
Other features and advantages of the invention will appear during the course of the following detailed description.